Step bunching in chemical vapor deposition of 6H– and 4H–SiC on vicinal SiC(0001) faces

Step bunching and terrace widening on 6H– and 4H–SiC epilayers on vicinal 0001 faces have been studied with atomic force microscopy (AFM) and transmission electron microscopy (TEM). Macroscopically, hill-and-valley structures are observed on off-oriented (0001) Si faces, whereas surfaces are rather flat on off-oriented (0001̄) C faces. High-resolution TEM analysis revealed that 3 bilayer-height steps are dominant on 6H–SiC and 4 bilayer-height steps on 4H–SiC. The distribution of step height and terrace width are also investigated.